Table of Contents
1
2
3
History 2
Disclaimer 2
Pin Configurations 3
3.1
Pin Descriptions 4
4
Overview 6
4.1
4.2
4.3
Block Diagram 7
Pin Descriptions 8
About Code Examples 9
5
AVR CPU Core 10
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
Introduction 10
Architectural Overview 10
ALU – Arithmetic Logic Unit 11
Status Register 12
General Purpose Register File 13
Stack Pointer 14
Instruction Execution Timing 14
Reset and Interrupt Handling 15
6
7
Memories 18
6.1
6.2
6.3
6.4
6.5
In-System Reprogrammable Flash Program Memory 18
SRAM Data Memory 18
EEPROM Data Memory 20
I/O Memory 26
General Purpose I/O Registers 26
System Clock 28
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
Clock Systems and their Distribution 28
Clock Sources 30
Default Clock Source 31
Low Power Crystal Oscillator 31
Calibrated Internal RC Oscillator 32
PLL 34
128 kHz Internal Oscillator 36
External Clock 36
i
AT90PWM2/3/2B/3B
4317J–AVR–08/10
ATMEL [ ATMEL ]
